We report the results of an aquaria-based experiment testing the effects of suspended particles generated during potential mining activities, on a common habitat-building coral species in the Azores, Dentomuricea aff. meteor. Coral fragments were maintained in 10-L aquaria and exposed to three experimental treatments for a period of four weeks at the DeepSeaLab aquaria facilities (Okeanos-University of the Azores): (1) control conditions (no added sediments); (2) suspended polymetallic sulphide (PMS) particles; (3) suspended quartz particles. Trace elements (Co, Cu, Mn) released from the resuspension of PMS particles to the water column in each aquaria were determined using passive sampling (DGT® Research Ltd) coupled with inductively coupled plasma mass spectrometry (ICPMS). DGT-holders were deployed in all aquaria and replaced every week (days 6, 13, 20, 27).

Metals in seawater: Measurements of metal content in seawater in the different experimental treatments